Starter motor as "boost/assist on pedal kart

[raceface32]

Hi, i have just got my son a pedal kart (free!) and had the idea of adding a small (maybe starter motor) electric motor with a push button on the steering wheel (a bit like KERS on F1 cars!).

The idea is for it to be an assist or boost for short periods of time, like uphill or for a bit of extra speed occasionally. The push button mounted on the steering wheel would enable a simple 12v circuit when it is pressed and held. When released it would break the circuit.

The motor would be mounted behind the seat on the frame and drive the rear axled via a pulley and belt.

The Kart has a lever operated free wheel mechanism, so my thoughts were that i could use a second switch on that to make sure the motor only comes on when the freewheel is operated, so it doesnt snap his legs off!

So with the free-wheel lever pulled, and the button pressed it would deliver power to the motor, when either is released, it cuts power to the motor.

As this would only be used in short bursts, it should get around the heat build up of prolonged use and a 12v motorbike battery should last a while before needing a charge.

My questions are:
1. Theoretically, will this work?
2. Do i need a controller for the starter? (I dont think so)
3. Is it better to use sprocket & chain or pulley and belt?
4. Is there somewhere in the UK that sells appropriate pulley/belts?

Thanks,

Rob

 

[j.concepcion54321]

it will work out just fine. you dont need a controller id just get a battery and hook it up with a solenoid and an on/off switch. the connection to the axle may be a little difficult though. we wont know for sure until we see it so when you get a chance post up some pics of the starter motor, and the pedal kart and well help you out as best as we can

 

[raceface32]

Thanks for the reply.

I havent yet got the starter, but i have a battery, well 2.

They are 12v 750w. Currently wired in series.

 

[raceface32]

I've been looking at some site and realised that i do not have a way to fix a drive sprocket or pulley to the axle, unless it comes with a boss and grub-screw setup like these pulleys:http://www.bearingstation.co.uk/products/Pulleys/HTD_Pulleys/HTD_Pulley_5mm

The issue with using belt and pulleys, for me, would be getting the right belt size and correct tension - i guess i would have to buy the belt and position them motor accordingly...

 

[j.concepcion54321]

thats true. are the wheels plastic? on my little pedal kart they are and what i did was that i drilled holes in them to match the end of my weedeater so that it just bolted up. it didnt go too fast or work the best but it didnt slip!!

If i were you id try to just get a small sprocket and just do what i said above with trying to just bolt it to the wheel. that way you can have it going directly to the wheel and wont mess up your idler setup thingy.

this isnt the best option but i figured id say something easy that might work. The better option would be to get a solid steel axle, some bearings, and 2 sprockets. that was you can have a live axle and can put as many sprockets as you want on it. it will work out alot better and will be alot safer.

where are you located? Depending on your area you could just serch around CL and see if you can find some good deals on a kart that way you can ensure that hell be having fun on a kart thats also safe. i messed around with those pedal karts when i was first starting and i realized how unsafe they were. they have small plastic bushings to hold the axle on, the axle isnt solid and its actually kind of hollow, and on top of that the wheels are plastic and arent really secured to the axle sort of just placed there so theyrenot meant for high speeds. even if it is just in the 'boost" form for short periods of time.

my suggestion would be leave the pedal kart as it is, and then buy a kart for cheap, or make one of your own. they make for really cool projects, just search around the forum youll see